BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 27 
INSECTS AFFECTING FOREST AND SHADE TREES 
COOPERATIVE SERVICE 
As in previous years, one of the most important activities of the Division of 
Forest Insect Investigations has been the cooperative service extended to the 
several Federal organizations administering timbered lands, such as the Forest 
Service, National Park Service, and Bureau of Indian Affairs, as well as to such 
emergency agencies as the Civilian Conservation Corps and the shelterbelt pro- 
gram, although advice to private timber owners has also been given. For the 
most part this cooperative service has consisted in surveys of forest-insect infes- 
tations, estimates of loss, recommendations as to proper control methods, esti- 
mates of the cost of such operations, and, in some cases, technical direction of 
control projects. 
Owing to increased activity in forest conservation in connection with emer- 
gency activities, such cooperative service has greatly increased in recent years. 
The administration of control programs is not usually included among the 
duties of the Division of Forest Insect Investigations, but pertains to the 
administrative agencies in charge of Federal lands. However, the Division has 
cooperated in a technical capacity in all of the larger control operations under- 
taken by the Forest Service. National Park Service, and Bureau of Indian 
Affairs. The total of expenditures for insect-control work is not obtainable, 
but in the western forests alone it amounted to several hundred thousand dol- 
lars. In Forest Service region 2 alone an expenditure of $174,574.47 was made 
in 1936 for combating forest insects. Much of this was for control work in 
connection with Civilian Conservation Corps camps. 
CONTROL PROGRAMS 
BLACK HILLS BEETLE 
As in past years, the principal control projects were undertaken against bark 
beetles of the genus Dendroctonus. Infestations by the Black Hills beetle were 
causing considerable damage, and more than $100,000 has been expended in 
their control in the central Rocky Mountain region, mostly through activities 
of the Civilian Conservation Corps camps. The largest of these projects were 
on the Medicine Bow National Forest in Wyoming and on the Uncompahgre 
and Montezuma National Forests in southern Colorado. The infestations in 
these areas have been brought under control and reduced to an endemic 
condition. 
MOUNTAIN PINE BEETLE 
In the northern Rocky Mountains no large-scale control projects were carried 
on during the year. The extensive control operations against the mountain 
pine beetle in the Coeur d'Alene which have been conducted for a number of 
years have resulted so successfully that no extensive work was necessary this 
year. While the extensive killing of trees continued in many of the lodgepole 
pine stands, only a few minor projects in strategic localities were undertaken 
by the Forest Service and Civilian Conservation Corps camps. 
WESTERN PINE BEETLE 
The salvage logging of beetle-killed timber was tried during the season of 
1935 on a sufficiently large scale to demonstrate its low cost and practicability 
under certain conditions. During the recent epidemic of the western pine 
beetle, a considerable amount of beetle-killed timber on the Shasta, Modoc 
and Lassen National Forests that would otherwise have been a total less has 
been moved quickly to the mill and salvaged. During the season two Lumber 
companies in this territory carried on operations that included the nulling of 
5,000.000 board feet of selected beetle-killed timber. Salvage work of this sort 
involves many entomological considerations, and both companies were guided 
in their operations by the advice of the Bureau. It was found thai by moving 
with modern logging equipment only infested and recently killed trees, salvage 
was profitable where the volume taken out did not run below WO board feet 
per acre. Logging costs on this basis were but slightly highei than by the 
regular method of cutting green timber on Forest Service sale contracts. The 
removal of infested trees had an appreciable effect upon the beetle population. 
